pySHPgeocode - This Python package reverse geocodes data points to shapefile regions. It is developed primarily for assigning administrative region codes to a set of geo coordinates (in standard latitude/longitude). All you need is a shapefile of the regions you want to geocode to.

Yahoo! GeoPlanet - Yahoo! GeoPlanet helps bridge the gap between the real and virtual worlds by providing an open, permanent, and intelligent infrastructure for geo-referencing data on the Internet. Includes some neighborhood names. Can be paired with Alpha Shapes below for rough lat/long and shape outlines. CC-BY.

GeoNames.org - The GeoNames geographical database covers all countries and contains over between 2 and 8 million placenames that are available for download free of charge. Readme for files and layout. Download list.

Natural Earth - Several thousand names of populated places gets you 1/2 of the world's population. What other database can claim that? ;)

NGA GeoNet Names Service - The Geographic Names Server is the official repository of standard spellings of all foreign place names, sanctioned by the United States Board on Geographic Names. The database also contains variant spellings (cross-references), which are useful for finding purposes. We are starting to hold the native script spellings of these names. All the geographic features in the database contain information about location, administrative division, and quality. The database can be used for a variety of purposes, including establishing official spellings of foreign place names, cartography, GIS, GEOINT, and finding places.

US Board on Geographic Names - The U.S. Board on Geographic Names is a Federal body created in 1890 and established in its present form by Public Law in 1947 to maintain uniform geographic name usage throughout the Federal Government. The Board promulgates official geographic feature names with locative attributes as well as principles, policies, and procedures governing the use of domestic names, foreign names, Antarctic names, and undersea feature names.

Placemaker - Yahoo! Placemaker is a freely available geoparsing Web service. It helps developers make their applications location-aware by identifying places in unstructured and atomic content and returning geographic metadata for geographic indexing and markup. Provided with free-form text, the service identifies places mentioned in text, disambiguates those places, and returns unique identifiers (WOEIDs) for each, as well as information about how many times the place was found in the text, and where in the text it was found.

Street Address: - An address consists of a street number, a street name, and a quadrant (NE, NW, SE, SW). The address number and street name are required.

Example: 441 4th ST NW

Input, gazetter: in a point XY, matches free text to points, polys, or street segment lines with addy ranges.

Result: New point location. The NAME normalized version of the address, including City, State, [Country], and ZIP+[4]. Optional: aggregated form placed back onto the POLYs/POINTS/etc used for matching.

Input, gazetter: a point XY or line segment, matches free text to points, polys, or street segment lines with addy ranges.

Result: New point location at mid zooms, new lines at high zooms, now with NAME normalized form and uniqueID added to their attributes. Optional: aggregated form placed back onto the POLYs/LINES/PTS used for matching.

Place, POI Names: - A place name consists of common place names (neighborhoods etc.) and public/institutional building names.